I have a 12" non commercial im looking to put a gear box on but having trouble finding one reasonable. I did find 2 commercial model QCGB's for around 500. anyone gone through the trouble of trying to mount on on a non commercial and succeded and willing to share what it takes?
-
Welcome back Guest! Did you know you can mentor other members here at H-M? If not, please check out our Relaunch of Hobby Machinist Mentoring Program!
atlas 12" commercial QCGB mounting to non commercial?
- Thread starter Redneck79
- Start date
- Joined
- Dec 25, 2011
- Messages
- 10,511
Around $500 to $600 has been about the going price on a QCGB for as long as I have been tracking such.
When Sears through Atlas started offering the QCGB circa 1951 they (or Atlas) made it so that it could be retrofitted to any one of the 12 earlier models.
That is only partially true. The bed, carriage and tailstock base of the 10" and 12" are the same or mostly the same in any given year. Except for the legs and where some of the holes in the bed are drilled and tapped. However, the 10" change gear models had a FWD-OFF-REV gearbox where the 12" had the tumbler type reversing. And there is a 1" vertical difference between where the lead screw and spindle are located.
Although most of the gears and some of the shafts inside are the same in the Atlas and Craftsman versions, the QCGB bodies or castings are not interchangeable.
The model of Atlas QCGB that will fit your 3/8" bed 12" is a 101.20140. While it may be possible to retrofit one of the others, and I have heard of it at least being attempted, you will be better off if you use the one intended for your machine. If you have a 101.07403, installing the GB turns it into either a 101.27430 or 101.27440, depending upon your bed length.
When Sears through Atlas started offering the QCGB circa 1951 they (or Atlas) made it so that it could be retrofitted to any one of the 12 earlier models.
That is only partially true. The bed, carriage and tailstock base of the 10" and 12" are the same or mostly the same in any given year. Except for the legs and where some of the holes in the bed are drilled and tapped. However, the 10" change gear models had a FWD-OFF-REV gearbox where the 12" had the tumbler type reversing. And there is a 1" vertical difference between where the lead screw and spindle are located.
Although most of the gears and some of the shafts inside are the same in the Atlas and Craftsman versions, the QCGB bodies or castings are not interchangeable.
The model of Atlas QCGB that will fit your 3/8" bed 12" is a 101.20140. While it may be possible to retrofit one of the others, and I have heard of it at least being attempted, you will be better off if you use the one intended for your machine. If you have a 101.07403, installing the GB turns it into either a 101.27430 or 101.27440, depending upon your bed length.